Two security officials loyal to Mahmoud Abbas, the Palestinian president, have been killed in Gaza, hospital officials said.
On Wednesday, gunmen attacked vehicles carrying the officials in Khan Younis in southern Gaza, leaving two people dead and a third official in a critical condition, according to hospital officials.
The gunmen have not been identified but Abbas's Preventative Security Forces blamed Hamas for the attacks.
Nour Odeh, Al Jazeera's correspondent in Gaza, said: "Despite this, both parties are saying the ceasefire still holds. Neither wants to be the one to break the ceasefire."
She also said: "These kinds of clashes are looked down upon by ordinary Palestinians."
The attack on Fatah-allied officials comes as security forces continue to search for an AFP photographer abducted on Monday.